It's time to break open the bananas and single out the shallots, says Andy Newman as he urges us all to avoid buying food wrapped in plastic

Prince William's stuttering attempts to interview Sir David Attenborough at the recent Davos summit (this journalism lark is not as easy as it looks, is it, Wills?) wasn't as embarrassing as it should have been – mainly due to the eloquent and effortless way in which Sir David articulated his views on saving the planet.

Attenborough has made a huge contribution to our understanding of the environment over the years, but surely one of his lasting legacies will be the way he brought to our attention, in the series Blue Planet 2, the massively damaging consequences of our love affair with plastic. It's hard to think of anything done by one individual which has had such a profound effect on so many people's behaviours.

Obviously, both supermarkets and consumers had to be forced to switch to more sustainable ways of carrying home their shopping, via the mandatory introduction of charging for single-use plastic bags. But the latest figures show that the move has resulted in a drop of more than 85 per cent in their use – which is an awful lot of waste not being dumped into our oceans, whichever way you look at it.

But carrier bags are just the tip of the (rapidly melting) iceberg, and our food retailers still have such a long way to go. Their head-in-the-sand refusal to tackle this issue until they are forced is breath-taking; it's almost like their whole business model is built on encouraging waste.

In my local Waitrose, for example, much of the fruit and veg can only be bought pre-packaged, wrapped in evil plastic, and in quantities which can only have been designed to lead to food being thrown away.

If you need a shallot, for example, you have to buy a bag of about 20 of them – when did you last see a recipe which needed that quantity? What's more, nature has already given the shallot a protective skin, so why wrap it further in plastic?

I have taken to tearing the bag open and just putting a single shallot in my trolley. It confuses them at the till when they try and weigh it, but generally they just put it through as an onion. If we all started doing this, maybe the supermarkets would get the message. It's a form of guerrilla shopping.

The same shop also sells bunches of bananas in plastic bags (see my picture). That's just crazy – again, nature has already given the banana a protective skin. It doesn't need a further wrapper which will pollute our oceans for centuries to come.

Thankfully, some supermarkets are starting to get the message. Marks & Spencer announced this month that they are to start selling nearly 100 lines of fruit and vegetables loose, free of all plastic packaging, with paper bags on hand to carry them home in (just like an old-fashioned greengrocer, in fact).

They say the move will reduce plastic waste by a staggering 580 tonnes over two years; it will also have the added benefit of reducing food waste, as shoppers will be able to buy exactly the quantity they need.

Meanwhile, Morrisons is bringing back traditional brown paper bags for loose fruit and veg, which they claim will lead to 150 million fewer plastic bags being used every year.

Don't be fooled into thinking that these measures are being introduced because of some sudden crisis of conscience by the companies involved. They are happening because these firms have realised that being seen to be environmentally unsound is rapidly becoming bad business. Consumer pressure is key to this kind of initiative happening. We all have a role to play here.

In an ideal world, we would all shop at places like Norwich Market, where top-quality fruit and veg is sold loose, and served in paper bags. But limited opening hours, coupled with Norwich City Council Traffic department's relentless efforts to prevent shoppers getting into the city centre, means that most of us will remain reliant on the big supermarkets.

If enough of us refuse to buy fruit and veg wrapped in plastic, and start tearing these bags apart and taking items loose to the till, eventually every supermarket will get the message. Because whatever they might say in their expensive TV commercials, they don't really care until it starts hitting their profits.